Gerald Shklar

An animal model for mucositis induced by cancer chemotherapy

Mucositis induced by chemotherapy is a painful and often dose-limiting side effect of cancer therapy. Furthermore, loss of the integrity of the oral epithelium often provides a microbial portal of entry and leads to sepsis. The present study describes the first animal model for chemotherapy-induced mucositis. The combination of three intraperitoneal injections of 5-fluorouracil at 5-day intervals and superficial mechanical mucosal irritation resulted in clinical breakdown of the oral mucosa characterized by ulcerative mucositis in Golden Syrian hamsters. Both clinical and histologic evaluation demonstrated that these changes were similar to those described in human beings and followed a pattern influenced by the degree of myelosuppression. This model should be of significance in establishing the stomatotoxicity of new chemotherapeutic agents, in evaluating medicaments to treat mucositis, and in studying the influence of oral mucosal breakdown on sepsis in myelosuppressed persons.

The selective cytotoxic effect of carotenoids and α-Tocopherol on human cancer cell lines in vitro

This study compares the toxic effects of the carotenoids, beta-carotene and canthaxanthin, and alpha-tocopherol (vitamin E) on human tumor cells and their normal counterparts in vitro. Seven different malignant cell lines were examined: oral carcinoma (two cell lines), breast (two cell lines), lung carcinoma (two cell lines), and malignant melanoma. The in vitro cell culture assays showed a consistent morphologic change in the affected tumor cells following treatment with carotenoid or vitamin E. A rounding of the tumor cells and eventual lifting off the tissue culture plate were observed. These changes were apparent after 1 to 5 hours of treatment depending on the tumor cell line. Associated with these observable cellular changes were quantitative reductions in proliferation (3H-thymidine proliferation) and succinic dehydrogenase activity (MTT assay). In addition, there was a noticeable change in protein expression, with an increased expression of a 70-kD protein following treatment with beta-carotene. This protein was associated with tumor cells showing a decrease in proliferation (oral carcinoma, malignant melanoma) but not with normal keratinocytes or melanocytes. These studies substantiate a selective cytotoxic effect on human tumor cell growth by carotenoids and alpha-tocopherol in vitro, and may provide an explanation of the therapeutic activity of these agents and their possible use in the treatment of premalignancy or early oral carcinoma.

Inhibition of hamster buccal pouch carcinogenesis by 13-cis-retinoic acid

Sixty-four male and female Syrian hamsters, 3 months of age and weighing 90 to 120 grams, were divided into four equal experimental groups. In animals of Groups 1 and 2 the left buccal pouch was painted three times weekly with a 0.5% solution of DMBA in heavy mineral oil. Group 2 animals also received 10 mg. of 13-cis-retinoic acid in peanut oil administered orally twice a week by pipette. Carcinogen retinoid were administered on alternate days. Group 3 animals served as controls, receiving only 13-cis-retinoic acid. Group 4 animals served as untreated controls. Four animals in each group (two males and two females) were killed at 10, 12, 14, and 16 weeks. The Group 2 animals, which received 13-cis-retinoic acid, exhibited a significant delay in DMBA carcinogenesis of buccal pouch mucosa, as studied both grossly and histologically. Both groups eventually demonstrated well-differentiated epidermoid carcinomas, but the tumors were smaller in the DMBA-retinoid animals.

Prevention of experimental oral cancer by extracts of Spirulina-Dunaliella algae.

An extract of Spirulina-Dunaliella algae was shown to prevent tumor development in hamster buccal pouch when a 0.1% solution of 7,12-dimethylbenz[a]anthracene (DMBA) in mineral oil was applied topically three times weekly for 28 weeks. The algae extract was delivered by mouth in continued dosages of 140 micrograms in 0.4 ml mineral oil three times per week. After 28 weeks, the animals given vehicle and untreated controls all presented gross tumors of the right buccal pouch. Animals fed canthaxanthin presented a notably and statistically significant reduction in tumor number and size compared with controls. Animals fed beta-carotene demonstrated a smaller but statistically significant reduction in tumor number and size. The algae animals presented a complete absence of gross tumors. However, microscopic sections of the buccal pouch in the algae group showed localized areas of dysplasia and early carcinoma-in-situ undergoing destruction.

Lichen planus as an oral ulcerative disease

Abstract Current research in oral lichen planus has primarily involved studies utilizing histochemistry, electron microscopy, and immunofluorescent antibody studies. Results to date have not expanded our knowledge concerning etiology and pathogenesis.

Tumor necrosis factor in experimental cancer regression with alphatocopherol, beta-carotene, canthaxanthin and algae extract.

Regression of established hamster buccal pouch carcinoma has recently been demonstrated in association with an induction of tumor necrosis factor alpha in macrophages. Regression of hamster buccal pouch tumors has also been demonstrated following the local injection of alphatocopherol, canthaxanthin and an extract of Spirulina-Dunaliella algae. The current study demonstrates that cancer regression is also accompanied by a significant induction of tumor necrosis factor in macrophages in the tumor area, suggesting a possible mechanism of tumor destruction. One hundred and forty young, male adult hamsters were divided into seven equal groups of 20 animals. Epidermoid carcinomas were induced in right buccal pouches by 14 weeks of painting, three times per week, of a 0.5% solution of 7,12-dimethylbenz(a)anthracene. Groups 1 and 2 were untreated and sham injected controls. Groups 3-7 had injected twice weekly into the right buccal pouches 0.1 ml (1.9 mg/ml of 13-cis-retinoic acid, canthaxanthin, algae extract, beta-carotene and alphatocopherol. After 4 weeks the tumors in groups 3-7 demonstrated varying degrees of regression and the animals were sacrificed and the right buccal pouches excised. Tumor necrosis factor alpha (TNF-alpha) was demonstrated by immunohistochemical techniques. A very significant increase in TNF-alpha positive macrophages was found in the tumor-bearing pouches of animals in groups 5-7. Smaller numbers of TNF-alpha-positive macrophages were found in group 4 pouches and a very slight increase in group 3 pouches.

Regression of experimental hamster cancer by beta carotene and algae extracts

The effect of algae extract on tumor regression was studied. Phycotene (extract of Spirulina and Dunaliella algae) 250 micrograms in 0.1 ml MEM (minimum essential medium) was injected locally into DMBA (7, 12 dimethylbenz(a)anthracene)-induced squamous cell carcinomas of hamster buccal pouch in 20 animals. DMBA-induced carcinomas in 20 hamsters were injected locally with beta carotene 250 micrograms in 0.1 ml MEM; DMBA-induced carcinomas in 20 animals were injected locally with canthaxanthin, 250 micrograms in 0.1 ml MEM, and DMBA-induced carcinomas in 20 animals were injected locally with 13-cis-retinoic acid, 250 micrograms in 0.1 ml MEM. Twenty animals with DMBA-induced carcinomas were sham-injected controls using 0.1 ml MEM. The various agents were injected into the tumor bearing right buccal pouches twice-weekly for four weeks. Total tumor regression was found in 30% of phycotene animals, 20% of beta carotene animals and 15% of canthaxanthin animals after four weeks. Partial tumor regression was found in the remaining 70% of phycotene animals, 80% of beta carotene animals and 85% of canthaxanthin animals. None of the 13-cis-retinoic acid animals had total tumor regression, but 70% showed partial regression. No tumor regression was found in the DMBA control group and the sham-injected group.

Jawbone cavities and trigeminal and atypical facial neuralgias

The possible role of dental and oral disease in the etiology of idiopathic trigeminal and atypical facial neuralgias has been examined. Among thirty-eight patients with idiopathic trigeminal neuralgia and twenty-three patients with atypical facial neuralgia, there was in nearly all instances a close relationship between pain experienced and the existence of cavities in alveolar bone and jawbone of the patients. The cavities were at the sites of previous tooth extractions and, although at times more than 1 cm. in a given diameter, were usually not detectable by x-rays. A new method for their detection and localization was developed empirically, based on the observation that peripheral infiltration of local anesthetic into or very close to the bone cavity rapidly abolished trigger and pain perception by patients during persistence of the anesthetic action. Histopathologic examination of bone removed from cavities by curettage revealed, in both idiopathic trigeminal and atypical facial neuralgias, a similar pattern characterized by a highly vascular abnormal healing response of bone. Some lesions presented a mild chronic inflammatory (lymphocytic) infiltration. Preliminary microbiologic studies of material from the walls of the cavities showed the existence within them of a complex, mixed polymicrobial aerobic and anaerobic flora. Treatment consisted of vigorous curettage of the bone cavities, repeated if necessary, plus administration of antibiotics to induce healing and filling-in of the cavities by new bone. Responses of patients to the above treatment consisted of marked to complete pain remissions, the longest of which has been for 9 years. Complete healing leads to complete and persistent pain remissions. It was concluded that in both idiopathic trigeminal and atypical facial neuralgias, dental and oral pathoses may be major etiologic factors.

Vitamin E inhibits experimental carcinogenesis and tumour angiogenesis

In an experiment in which vitamin E inhibited carcinogenesis, it was found that tumour angiogenesis and tumour growth-factor alpha (TGF alpha) expression were also inhibited. Forty male golden hamsters were divided into four equal groups. Group 1 animals had the left buccal pouches painted three times weekly with 7,12-dimethylbenz(a)anthracene (DMBA) for 14 weeks. Group 2 animals had the same procedure of DMBA applications but also received alpha tocopherol. Groups 3 and 4 were vitamin E and untreated controls. Angiogenesis was studied with factor 8-related antigen (F8-RA) which identifies endothelial cells. TGF alpha was studied with the appropriate antibody. Staining was effected by the standard avidin-biotin horseradish peroxidase system. Mean tumour volume was significantly lower in the DMBA-vitamin E group compared to the tumour control group. Angiogenesis was significantly inhibited in the DMBA-vitamin E group and TGF alpha expression was also inhibited. It is suggested that inhibition of tumour angiogenesis by vitamin E may be an additional mechanism for the anticancer action of vitamin E.

The effectiveness of a mixture of β-carotene, α-tocopherol, glutathione, and ascorbic acid for cancer prevention

Abstract Previous studies have shown that β‐carotene and α‐tocopherol can act synergistically to inhibit the growth of experimentally induced oral cancer. The initial studies on the synergistic anticancer activity of antioxidants have been extended to include reduced glutathione and ascorbic acid. Sixty male hamsters (4–5 wks old) were divided into six equal groups. Groups 1–6 were treated with 7,12‐dimethylbenz[a]anthracene (DMBA) (0.5% solution). Group 2 received a mixture containing equal amounts of β‐carotene, dl‐α‐tocopherol (vitamin E), glutathione, and l‐ascorbic acid (vitamin C) (12.5 μg) delivered orally by pipette. Groups 3–6 were treated with β‐carotene alone (50 μg), vitamin E alone (50 μg), glutathione (50 μg) alone, and vitamin C alone (50 μg). Animals were euthanized at 12 and 14 weeks. Tumors were counted and measured, and tumor burden was calculated for each experimental group. The mixture of antioxidants significantly reduced tumor burden, whereas the β‐carotene, vitamin E, and reduced g...